JPH09152766A - Developing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely detect whether or not the sufficient amount of magnetic toner exists by a magnetic permeability detector, by making the toner periodically flow toward a magnetic permeability detection surface, also analyzing the output signal of the magnetic permeability detector and discriminating the toner amount. SOLUTION: A toner detecting means 80 includes the related magnetic permeability detector 82 to one end part of a toner carrying path 36. The leading end part of the detector 82 is positioned in an opening 84, the detection surface 86 of the detector 82 is exposed on the toner carrying path 36 through the opening 84. The detection surface 86 is inclined at an inclined angle θ with respect to the horizontal plane. And, the output voltage of the detector 82 is changed in accordance with a magnetic resistance near the detection surface 86. That is, when a large quantity of magnetic material exists near the detection surface 86 and the magnetic resistance is small, the large output voltage is generated, meanwhile, when a small amount of magnetic material exists and the magnetic resistance is large, a small output voltage is generated. Thus, even when the toner is slightly magnetic, the toner is surely detected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device used for developing an electrostatic latent image into a toner image in an image forming machine such as an electrostatic copying machine or a laser printing machine, and more particularly, to a consumed magnetic field. The present invention relates to a developing device equipped with a toner detector for detecting whether or not a sufficient amount of toner is present.

[0002]

2. Description of the Related Art As is well known, in image forming machines such as electrostatic copying machines and laser printers, an electrostatic latent image is formed on a photoconductor and the electrostatic latent image is developed into a toner image. . A typical example of a developing device that develops an electrostatic latent image into a toner image includes a developing container, a developer applying unit, and a toner supplying unit. The developer container contains a so-called two-component developer consisting of carrier particles and toner, or a so-called one-component developer consisting only of toner. The developer applying means conveys the developer existing in the developing container to the developing area and applies it to the electrostatic latent image to be developed, and thus applies the toner to the electrostatic latent image to develop the toner image. The toner supply unit supplies the toner into the developing container according to the consumption of the toner in the developing container. Toner supply means is usually provided with toner detection means for detecting whether or not a sufficient amount of toner is present. When the amount of toner existing in the toner supply unit decreases, the toner detection unit detects this and warns the user that it is necessary to supply toner to the toner supply unit. As the toner detecting means, a toner detecting means called a photo interrupter is generally used. The toner detecting means includes a light emitting element and a light receiving element, and when the toner supplying means has a sufficient amount of toner, the optical path between the light emitting element and the light receiving element is blocked by the toner. When the amount of toner existing in the means is reduced, the light from the light emitting element is received by the light receiving element, and it is detected that the amount of toner existing in the toner supply means is reduced.

[0003]

When a toner detecting means called a photo interrupter is used,
It is necessary to additionally form a detection site defined by a transparent member on the toner supply means. The light emitting element and the light receiving element of the toner detecting means are arranged on both sides of the detection portion,
When there is a sufficient amount of toner at the detection site, the optical path between the light emitting element and the light receiving element is blocked by the toner, but when there is no sufficient amount of toner at the detection site, the light emitting element emits light. The light is received by the light receiving element. Furthermore, if toner adheres to the inner surface of the transparent member that defines the detection site, the optical path between the light emitting element and the light receiving element is blocked even though there is not a sufficient amount of toner at the detection site. It is also necessary to attach cleaning means for cleaning the inner surface of the transparent member that defines the site.

On the other hand, when the developer contained in the developing container is a two-component developer consisting of carrier particles and toner, generally, when the ratio of the toner in the developer, that is, the toner concentration decreases, the developer In view of the increase in magnetic resistance, a magnetic permeability detector whose output voltage changes according to the magnetic resistance is used to detect the toner concentration in the developer. When the toner used is a magnetic toner, it may be intended to use a magnetic permeability detector for detecting the toner itself instead of the toner detecting means called the photo interrupter. However, when the magnetic permeability detector is used for detecting the toner itself, there are the following problems to be solved. As is well known to those skilled in the art, the output voltage of the magnetic detector fluctuates not only due to changes in magnetic resistance but also due to changes in temperature, but the magnetic strength of the toner is comparable to that of the developer containing carrier particles. Because of its low value, if toner detection is attempted based on the absolute value of the output voltage value of the magnetic permeability detector, there is a risk that erroneous detection will occur due to changes in ambient temperature. Further, in order to detect whether or not a sufficient amount of toner is present in the predetermined area of the toner supply means, it is necessary to expose the magnetic permeability detection surface of the magnetic permeability detector to the predetermined area of the toner supply means. However, if toner adheres to the exposed magnetic permeability detection surface, a sufficient amount of toner exists due to the toner adhered to the magnetic permeability detection surface even if sufficient toner does not exist in the predetermined area. There is also a possibility that it may be erroneously detected as being present.

As disclosed in Japanese Unexamined Patent Publication No. 7-56384, the weight of the two-component developer has recently been increased in place of containing a relatively expensive CCA (charge control agent). A toner containing a magnetic material such as magnetite in a proportion of 0.1 to 5.0% has been proposed. Such a toner, which is also called a CCA-less toner, is a so-called fine magnetic toner having some magnetism.
When the toner to be detected is a micro-magnetic toner, the above problem when using the magnetic permeability detector for toner detection is particularly remarkable.

The present invention has been made in view of the above facts, and its main technical problem is to determine whether or not a sufficient amount of magnetic toner exists in a predetermined area by using a magnetic permeability detector. Appropriately avoiding false detections
It is to provide a new and improved developing device.

[0007]

DISCLOSURE OF THE INVENTION The inventors of the present invention have diligently studied the relationship between magnetic toners, particularly micromagnetic toners, and the detection characteristics of magnetic permeability detectors, and as a result, have determined whether a sufficient amount of toner is present. The toner is made to flow periodically toward the magnetic permeability detection surface of the magnetic permeability detector, which is exposed to the predetermined area for detecting the magnetic field, and the output signal of the magnetic permeability detector is appropriately analyzed and determined. By fake,
It has been found that the above main technical problems can be achieved.

That is, according to the present invention, as a developing device that achieves the above-mentioned main technical problems, the developing device is provided with a toner detecting means for detecting whether or not a sufficient amount of magnetic toner is present in a predetermined area. In the apparatus, the toner detecting means has a magnetic permeability detector having a magnetic permeability detecting surface exposed in the predetermined region, and a toner existing in the predetermined region is directed toward the magnetic permeability detecting face of the magnetic permeability detector. A periodic flow means for causing periodic flow, and a determination means for analyzing an output signal of the magnetic permeability detector to determine whether or not a sufficient amount of toner is present in the predetermined area is included. A developing device is provided.

A typical example of the toner is a micromagnetic toner containing 0.1 to 5.0% by weight of a magnetic material. Preferably, the magnetic permeability detector has a form in which the output voltage changes according to the magnetic resistance, and the determining means makes the determination based on the amount of change in the output voltage. Alternatively, the determination means makes the determination based on the integrated value of the output voltage during the predetermined time. The periodic flow means is constituted by a rotary flow member that is rotationally driven and has a tip portion slidingly rubbing the magnetic permeability detection surface of the magnetic permeability detector, and a rotation center axis line of the rotary flow member is Suitably, it extends substantially parallel to the permeability detection surface of the permeability detector. The rotary flow member is conveniently formed from a synthetic resin film such as a polyethylene terephthalate film. The permeability detecting surface of the permeability detector has an inclination angle θ of 0 ° <θ ≦ 90 °, particularly 30 ° ≦ θ ≦ 60 ° with respect to the horizontal, and the tip of the rotary flow member has the permeability. It is preferable to rotate the magnetic permeability detection surface of the magnetic susceptibility detector in a direction in which the magnetic susceptibility detection surface rubs from below to above. A cleaning unit that acts on the rear surface in the rotation direction of the rotating fluid member to remove the adhered toner can be provided. The cleaning means is composed of a rotary cleaning member that is driven to rotate, and a rotation center axis of the rotation cleaning member extends substantially parallel to a rotation center axis of the rotary fluid member, and a rotation direction of the rotation cleaning member and It is preferable that the rotation direction of the rotary flow member is opposite to that of the rotary flow member, and that the tip of the rotary cleaning member acts on the rear surface of the rotary flow member in the rotary direction. The rotary cleaning member is also preferably formed of a synthetic resin film such as polyethylene terephthalate film. The predetermined region is in the magnetic toner transport path, and at least one factor relating to toner transport changes between the upstream side and the downstream side of the predetermined region, so that toner retention is generated in the predetermined region. Is preferred. The toner retention is such that the carrying capacity of the upstream toner carrying means arranged upstream of the predetermined area is larger than the carrying capacity of the downstream toner carrying means arranged downstream of the predetermined area. Due to
Alternatively, it may be generated due to the toner transport direction being abruptly changed in the predetermined region. Preferably, the predetermined region is formed with a recess for forming a toner reservoir, and the periodic flow means also acts on the toner existing in the recess. In a preferred embodiment,
The developing device includes a developing container, a developer applying unit for applying a developer existing in the developing container to an electrostatic latent image to be developed, and a toner supplying unit for supplying a magnetic toner to the developing container. A hopper container in which the toner supply means is provided with a toner transport path having a toner receiving port and a toner discharge port communicating with the developing container;
And a transport unit for transporting the magnetic toner through the toner transport path, and the predetermined region is in the toner transport path formed in the hopper container. The developer present in the developing container is a two-component developer composed of carrier particles and magnetic toner. Further, the toner supply means includes a toner cartridge that is replaceably mounted, and the magnetic toner accommodated in the toner cartridge is fed to the hopper container through the toner receiving port.

[0010]

According to the developing device of the present invention, the toner is periodically made to flow toward the magnetic permeability detecting surface of the magnetic permeability detector so that the output signal of the magnetic permeability detector is periodically changed and the magnetic permeability is also changed. The output signal of the detector is not the absolute value itself, but the output signal is appropriately analyzed, for example, based on the variation of the output voltage during a predetermined time, or based on the integrated value of the output voltage during a predetermined time, Since it is determined whether or not a large amount of toner is present, erroneous detection does not occur even if the output signal of the magnetic permeability detector is changed due to a change in ambient temperature. Further, since the toner periodically flows on the magnetic permeability detecting surface of the magnetic permeability detector, toner is effectively prevented from adhering to the magnetic permeability detecting surface of the magnetic permeability detector. False detection due to toner adhesion to the toner can be effectively avoided. Further, in the developing device of the present invention, when the toner of the standard which is substantially non-magnetic or has a considerably large magnetism is replenished, the toner detecting means cannot judge that there is sufficient toner, and It is also possible to let the user recognize that the nonstandard toner has been erroneously supplied.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of a developing device constructed according to the present invention will be described below in more detail with reference to the accompanying drawings.

Referring to FIGS. 1 and 2, the developing device shown in the drawing comprises a developing container 2 and a toner supplying means 4 for supplying toner to the developing container 2. As schematically shown in FIG. 2, the developer container 2 is provided with a developer applying unit 6. The developer applying means 6 includes a rotating sleeve member and a stationary magnet member arranged in the rotating sleeve member, and holds the developer existing in the developing container 2 on the peripheral surface of the rotating sleeve member to develop the developing area. 8 is applied to the electrostatic latent image formed on the peripheral surface of the rotating drum 10 in the developing area 8 to develop the electrostatic latent image into a toner image. The developer may be a two-component developer composed of carrier particles and toner. In the developing container 2, a developer agitating / conveying means (not shown) for agitating the developer to charge the toner and conveying it through a required conveying path.
Are also provided. Further, a toner concentration detecting means (not shown) for detecting the toner concentration in the developer in the developing container 2 is also provided, and when the toner concentration in the developer becomes a predetermined value or less, the toner is supplied. The means 4 is operated to supply the toner from the toner supply means 4 to the developing container 2. The toner concentration detecting means can be composed of a magnetic permeability detector whose output voltage changes according to the magnetic resistance of the developer. The developing container 2, the developer applying means 6, the developer stirring means, and the toner concentration detecting means arranged therein do not constitute the novel features of the developing device shown in the drawings constructed according to the present invention. The configuration of itself may be a well-known form, and therefore the detailed description of these configurations will be omitted in this specification.

Continuing the description with reference to FIGS. 1 and 2,
The toner supply unit 4 is composed of a hopper container 12 and a toner cartridge 14. The hopper container 12 includes a box-shaped container body 16 having a substantially rectangular shape as a whole. The container body 16 has a bottom wall 26 with four side walls 18, 20, 22 and 24. As can be understood by referring to FIG. 2, the upper surface of the main portion (a portion other than the recessed portion described later) of the bottom wall 26 has two arcuate portions 28 and 3 located adjacent to each other.
Has zero. Two arcuate portions 28 and 30 are provided on the bottom wall 26.
An upright partition wall 32 extending therethrough is formed. Partition wall 3
2 extends on the bottom wall 26 in the longitudinal direction (direction perpendicular to the paper surface in FIG. 2), but does not exist at both ends of the container body 16 in the longitudinal direction. Thus, inside the container body 16, toner transport paths 34 and 36 which are partitioned by the partition wall 32 and extend parallel to each other are defined. The toner transport paths 34 and 36 are defined at both ends of the container body 16, that is, the partition wall. The portion where the wall 32 does not exist is communicated in the lateral direction. A toner discharge port 38 is formed in the bottom wall 26 at an intermediate portion of the toner transport path 36.
The toner discharge port 38 is communicated with the developing container 2 disposed below the hopper container 12, and the toner is discharged from the hopper container 12 to the developing container 2 through the toner discharge port 38 as will be described in detail later. Is supplied. The upper surface of the hopper container 12 is covered by a substantially flat upper wall 40. A toner receiving port 42 is provided in the upper wall 40 at a portion corresponding to one end of the toner transport path 34.

The toner conveying paths 34 and 36 formed in the hopper container 12 are provided with conveying means indicated by numeral 44 as a whole. The transport unit 44 includes a rotary shaft 46 extending along the toner transport path 34 and a rotary shaft 48 extending along the toner transport path 36.
The rotating shafts 46 and 48 are the side walls 18 and 2 of the hopper container 12.
It is mounted rotatably between zero. Rotating shafts 46 and 48
Is drivingly connected to an electric motor (not shown) via an appropriate transmission mechanism (not shown) such as a transmission gear, and when the electric motor is energized, the rotary shaft 46 is rotated by an arrow 50.
The rotary shaft 48 is driven to rotate in the direction indicated by arrow 52 in the direction indicated by arrow 52. At both ends of the rotary shaft 46, there are discs 47 and 4
9 are formed. A spiral blade 54 that extends continuously is formed on the main portion of the rotating shaft 46, that is, on the portion excluding both ends. At each of both ends of the rotary shaft 46, one rectangular feed piece 56 and 58 extending in the radial direction from the peripheral surface of the rotary shaft 46 is formed. The axially outer ends of the feed pieces 56 and 58 are connected to the inner surfaces of the disks 47 and 49. Discs 59 and 61 are also formed at both ends of the other rotating shaft 48. Two spiral blades 60 and 62 are formed on the main part of the rotary shaft 48, that is, on the part excluding both ends. Then, between the spiral blade 60 and the spiral blade 62, four feeding pieces 64 extending in the radial direction from the peripheral surface of the rotary shaft 48 are formed at an angular interval of 90 degrees from each other. The portion where the four feeding pieces 64 are formed corresponds to the portion where the toner discharge port 38 is formed, and the four feeding pieces 64 are located above the toner discharge port 38. On each of both ends of the rotary shaft 48, one rectangular feed piece 66 and 68 extending in the radial direction from the peripheral surface of the rotary shaft 48 is formed. The axially outer ends of the feeding pieces 66 and 68 are connected to the inner surfaces of the disks 59 and 61. At one end of the rotary shaft 48, in addition to the feed piece 66, two short spiral blades 7 extending over an angle range of about 180 degrees.
0 and 72 are also formed. The two short spiral blades 70 and 72 are arranged diametrically opposite to each other with respect to the feed piece 66.

As clearly shown in FIG. 1, the toner cartridge 14 of the toner supply means 4 is in the form of a hollow container.
It is replaceably mounted above the hopper container 12. A toner supply port (not shown) is formed on the bottom surface of the toner cartridge 14. The toner supply port is sealed by an appropriate sealing member until the toner cartridge 14 is mounted at a required position, but is opened when the toner cartridge 14 is mounted at a required position and is formed on the upper wall 40 of the hopper container 12. The toner is received by the toner receiving port 42. Further, inside the toner cartridge 14, a toner conveying means (not shown) for conveying the toner contained therein toward the toner supply port is also arranged. The toner conveying means can be composed of a rotating spiral blade or the like. The toner accommodated in the toner cartridge 14 is dropped into the hopper container 12 through the toner supply port formed in the toner cartridge 14 and the toner receiving port 42 formed in the hopper container 12. In the hopper container 12, when an electric motor (not shown) is urged to rotate the rotary shafts 46 and 48 in the directions indicated by arrows 50 and 52, they are formed at one end of the rotary shaft 46. Due to the action of the feeding piece 56, the toner dropped through the toner receiving port 42 is forced into the toner conveying path 34. Then, due to the action of the spiral blade 54 formed on the rotary shaft 46, the toner is transported along the toner transport path 34 in the direction indicated by the arrow 74. Hopper container 1
At the other end of 2, the toner is transported from the toner transport path 34 to the toner transport path 36 by the action of the feed piece 58 formed on the rotating shaft 46, as shown by the arrow 76.
Then, in the toner carrying path 36, the toner is carried toward the toner discharge port 38 in the direction shown by the arrow 78 by the action of the spiral blades 70, 72 and 60 formed on the rotary shaft 48. Next, the toner is forced downward by the action of the feeding piece 64 formed on the rotary shaft 48, drops through the toner discharge port 38, and is supplied to the developing container 2. The toner not dropped through the toner outlet 38 is further conveyed in the direction shown by the arrow 78 by the action of the spiral blade 62 formed on the rotary shaft 48, and is formed on the rotary shaft 48 at one end of the hopper container 12. By the action of the feeding piece 68, the toner is conveyed from the toner conveying path 36 to the toner conveying path 34.

The toner contained in the toner cartridge 14, and thus discharged from the toner cartridge 14,
As a preferable example of the toner which is conveyed through the toner conveying paths 34 and 36 formed in the hopper container 12 and is supplied to the developing container 2, the toner disclosed in JP-A-7-56384 can be cited. . Such a toner contains 0.1 to 5.0% by weight of a magnetic material such as magnetite, instead of containing a relatively expensive CCA (charge control agent).
Such a toner is usually called a CCA-less toner, and is a so-called micro-magnetic toner having some magnetism due to the contained magnetic material.

Thus, in the illustrated developing device constructed according to the present invention, the toner detecting means 80 for detecting whether or not a sufficient amount of toner is present in a predetermined area in the hopper container 12 is provided. Is important. Referring to FIGS. 1 and 2, the toner detecting means 80 includes a magnetic permeability detector 82 arranged in association with one end of the toner conveying path 36. More specifically, a circular opening 84 is formed in the bottom wall 26 to the side wall 24 of the hopper container 12. The tip of the magnetic permeability detector 82 is positioned in the opening 84, and the circular tip surface of the magnetic permeability detector 82, that is, the magnetic permeability detecting surface 86 is exposed to the toner transport path 36 through the opening 84. It is preferable that the exposed magnetic permeability detection surface 86 is inclined with respect to the horizontal at an inclination angle θ of 0 ° <θ ≦ 90 °, particularly 30 ° ≦ θ ≦ 60 °. As the magnetic permeability detector 82 itself, for example, a differential transformer type magnetic permeability detector sold under the trade name “TS0524LB” by TDK Corporation can be suitably used as the high sensitivity magnetic permeability detector. . In such a magnetic permeability detector 82, the output voltage changes according to the magnetic resistance in the vicinity of the magnetic permeability detecting surface 86, that is, the magnetic permeability detecting surface 86.
When a relatively large amount of magnetic material is present in the vicinity and the magnetic resistance is small, a relatively large output voltage is generated and the magnetic permeability detection surface 8
When the magnetic material existing near 6 is a relatively small amount and the magnetic resistance is large, a relatively small output voltage is generated.

Continuing the description with reference to FIGS. 1 and 2,
The hopper container 12 is also provided with a periodic flow means 88 and a cleaning means 90 in association with the magnetic permeability detector 82. The periodic flow means 88 in the illustrated embodiment is composed of a rotary flow member 92 fixed to a feed piece 66 formed at one end of the rotary shaft 48. The rotary flow member 92 is preferably formed of an appropriate synthetic resin film such as a polyethylene terephthalate film. The rotary fluid member 92 is provided with the arrow 5
It has a rectangular shape extending in the radial direction of the rotation shaft 48 from a base portion fixed to the front side surface by an appropriate method such as adhesion when viewed in the rotation direction shown by 2. The extension length of the rotary flow member 92 is
It is set to be considerably longer than the length from the central axis of the rotary shaft 48 to the magnetic permeability detection surface 86 of the magnetic permeability detector 82. As will be described in more detail later, when the rotary shaft 48 is driven to rotate in the direction shown by the arrow 52, the rotary flow member 92 is also driven to rotate in response to this, and the tip portion thereof detects the magnetic permeability of the magnetic permeability detector 82. The surface 86 is rubbed from bottom to top. The rotating shaft 48 and the magnetic permeability detecting surface 86 of the magnetic permeability detector 82.
Are substantially parallel to each other, and therefore the rotation center axis of the rotary flow member 92 constituting the periodic flow means 88 and the magnetic permeability detection surface 86 of the magnetic permeability detector 82 are substantially parallel to each other. The cleaning means 90 is composed of a rotary cleaning member 94 fixed to the feed piece 58 formed at one end of the rotary shaft 46. The rotary cleaning member 94 is also preferably formed of an appropriate synthetic resin film such as a polyethylene terephthalate film. The rotary cleaning member 94 has a rectangular shape extending in the radial direction of the rotary shaft 46 from a base fixed to the feed piece 58 by an appropriate method such as bonding. The extension length of the rotary cleaning member 94 is set to be considerably longer than the length from the central axis of the rotary shaft 46 to the boundary region between the toner transport path 34 and the toner transport path 36. As will be described in more detail later, when the rotary shaft 46 is driven to rotate in the direction indicated by the arrow 50, the rotary cleaning member 94 is also driven to rotate in response to this, and the tip end thereof constitutes the periodic flow means 88. It acts on the rear surface of the flow member 92 in the rotational direction. The rotary shaft 46 and the rotary shaft 48 are substantially parallel to each other, and thus the rotation center axis of the rotary flow member 92 that constitutes the periodic flow means 88 and the rotary cleaning member 94 that constitutes the cleaning means 90.
Is substantially parallel to the rotation center axis of the. Further, since the rotating direction of the rotating shaft 46 and the rotating direction of the rotating shaft 48 are opposite to each other, the rotating fluidizing member 9 constituting the periodical fluidizing means 88.
2 rotation direction and rotation cleaning member 9 that constitutes the cleaning means 90
It is opposite to the rotation direction of No. 4.

As clearly shown in FIG. 2, the hopper container 1
At one end of No. 2, the partition wall 32 does not exist, and in addition to the partition detector 32, the periodic flow means 88, and the cleaning means 90, corresponding to the arrangement region, the partition wall 32 is immersed below the other portions. The recessed portion 96 is formed. The recessed portion 96 is defined by making the upper surface of the bottom wall 26 not a shape having two arcuate portions but a single arcuate shape that is recessed below the lowermost portion of the two arcuate portions. The length of the tip of the rotary flow member 92 that constitutes the periodic flow means 88 is set so that the surface of the recess 96 is also rubbed.

As schematically shown in FIG. 3, the output signal of the magnetic permeability detector 82 is sent to the discriminating means 98 which can be constituted by a microprocessor, and the discriminating means 98 outputs the output signal of the magnetic permeability detector 82. By performing an appropriate analysis, it is determined whether or not there is a sufficient amount of toner in a predetermined area of the hopper container 12, that is, one end of the toner transport path 36. If this point is explained further in detail, the toner is still left in the toner cartridge 14, and the hopper container 1
When the toner is fed from the toner cartridge 14 into the hopper container 12 in response to the toner feeding from the developing container 2 to the developing container 2, the toner carrying paths 34 and 36 in the hopper container 12 are shown in FIG. A sufficient amount of toner 10
0 is present. In such a state, the rotary shaft 48
When the toner is rotated in the direction indicated by the arrow 52, the periodical flow means 88 constituted by the rotary flow member 92 arranged on the rotary shaft 48 is attached to the toner 100 present at one end of the toner transport path 36. The toner 100 is caused to flow cyclically, that is, every rotation, while pressing the toner 100 from the lower side to the upper side of the magnetic permeability detection surface 86 of the magnetic permeability detector 82. When the tip of the rotary flow member 92 rubs against the magnetic permeability detection surface 86 of the magnetic permeability detector 82, the toner 100
Is pressed against the magnetic permeability detection surface 86, the magnetic resistance detected by the magnetic permeability detector 82 is considerably small, and therefore the output voltage of the magnetic permeability detector 82 is considerably large. On the other hand, the tip of the rotating fluid member 92 is the magnetic permeability detection surface 8 of the magnetic permeability detector 82.
6, the toner 10 on the magnetic permeability detection surface 86
The pressing of 0 disappears, so that the output voltage of the magnetic permeability detector 82 decreases. However, as will be easily understood by referring to FIG. 4, when the toner 100 in a sufficient amount is present in the hopper container 12, the tip of the rotary flow member 92 passes through the magnetic permeability detection surface 86. Immediately after that, a large amount of toner 100 still exists near the magnetic permeability detection surface 86. Therefore, the rotary flow member 92
The amount of decrease in the output voltage of the magnetic permeability detector 82 after the tip of the magnetic disk passes the magnetic permeability detecting surface 86 is relatively small. On the other hand, when the toner 100 in the toner cartridge 14 is substantially exhausted and the toner 100 is continuously supplied from the hopper container 12 to the developing container 2 even after that, as shown in FIG. The amount of 100 is significantly reduced. In such a state,
When the rotary shaft 48 is rotated in the direction indicated by the arrow 52, the tip end portion of the rotary flow member 92 arranged on the rotary shaft 48 causes the toner 100 to flow and the magnetic permeability detection surface 86 of the magnetic permeability detector 82 is exposed. When pressed, the output voltage of the magnetic permeability detector 82 is relatively large due to the toner 100. However, as will be easily understood by referring to FIG. 5, immediately after the tip of the rotary flow member 92 has passed the magnetic permeability detection surface 86, a small amount of toner 100 is present in the vicinity of the magnetic permeability detection surface 86. It no longer exists and thus the output voltage of the permeability detector 82 drops significantly.

FIG. 6 shows an example of actually measured data of the output voltage of the magnetic permeability detector 82 obtained by carrying out the following experiment.
In the experiment, a hopper container 12 having a configuration as shown in FIGS. 1 and 2 was used, and the hopper container 12 was filled with the above-described fine magnetic toner. Then, the rotating shaft 4
6 and 48 were continuously rotated, and the toner 100 was discharged from the inside of the hopper container 12 through the toner discharge port 38.
The toner 100 was not supplied from the toner receiving port 42 to the hopper container 12. Therefore, the amount of the toner 100 in the hopper container 12 was gradually reduced with the lapse of time. In the actual measurement data shown in FIG. 6, a relatively large amount of toner 100 was present in the hopper container 12 at time T1. During this period, it is understood that the fluctuation amount L1 of the output voltage of the magnetic permeability detector 82 due to the periodical flow of the toner 100 by the rotating flow member 92 is relatively small. From time T1 to time T2, the amount of change in the output voltage of the magnetic permeability detector 82 gradually increases. When the time T2 is exceeded, the fluctuation amount L2 of the output voltage of the magnetic permeability detector 82 stabilizes at a relatively large value. After the time T2, the amount of the toner 100 existing in the region where the magnetic permeability detector 82 is arranged is remarkably reduced, and the state is as shown in FIG.

Referring to FIG. 3 together with FIGS. 4 to 6, the discrimination means 98 is shown in FIG. 6 according to the output signal of the magnetic permeability detector 82, that is, the amount of the toner 100 in the hopper container 12. The output voltage that changes as described above is analyzed and determined. As can be clearly understood from the example of the actual measurement data shown in FIG. 6, a sufficient amount of the toner 1 is stored in the hopper container 12.
When 00 is present, the fluctuation amount L1 of the output voltage of the magnetic permeability detector 82 when the rotary shaft 48 is rotated is relatively small. On the other hand, when the amount of the toner 100 in the hopper container 12 is significantly reduced, the rotating shaft 48
The fluctuation amount L2 of the output voltage of the magnetic permeability detector 82 when rotated is considerably large. In consideration of such a fact, the determination unit 98 analyzes and determines the variation amount of the output voltage when the rotation shaft 48 is rotated and the periodic flow unit 88 is caused to periodically flow the toner. For example, the difference L between the maximum value and the minimum value is calculated for each waveform of the output voltage, and when the L exceeds a predetermined threshold value for a predetermined number of times (for example, 3 times), the hopper container 12 is sufficiently filled. Amount of toner 100
Does not exist, in other words, the toner 1 in the hopper container 12
A toner replenishment signal indicating that the amount of 00 has been significantly reduced. If desired, instead of this, the maximum value of the output voltage of the magnetic permeability detector 82 during a predetermined time, for example, 10 seconds (the time interval indicated by D1 in the actual measurement data example of FIG. 6 was 10 seconds), The difference L from the minimum value is calculated, and it is determined whether or not the difference L is larger than a predetermined threshold value. If the difference L is larger than the predetermined threshold value, a sufficient amount of toner 100 is stored in the hopper container 12. It is also possible to generate a toner replenishment signal indicating the absence. Discrimination means 9
8 generates a toner replenishment signal, the warning means 102, which may be a warning lamp, is energized, thus requiring the toner replenishment, in other words, the toner cartridge 1
The user is warned that it is necessary to replace 4 with a new one.

According to experiments conducted by the present inventors, the output voltage of the operating transformer type permeability detector 82 described above is affected by the ambient temperature, and when the ambient temperature rises, the output of the permeability detector 82 is increased. The voltage value is increased, and the output waveform in FIG. 6 tends to be moved upward as a whole. Toner 100 is a fine magnetic toner, and toner 100
When the magnetic resistance of is relatively large, the magnetic permeability detector 82
The absolute value of the output voltage of is relatively small. Therefore, if a determination is made based on the absolute value of the output voltage of the magnetic permeability detector 82,
It is not uncommon to make an error in the determination due to the ambient temperature. However, the change in the output voltage of the magnetic permeability detector 82 due to the change in the ambient temperature tends to cause the output waveform in FIG. 6 to move upward or downward as a whole. Therefore, even if the ambient temperature changes, the change in the variation amount (difference between the maximum value and the minimum value) of the output voltage during the predetermined time is relatively small. Therefore, as described above, the rotating shaft 4
When 8 is rotated and the periodic flow means 88 is causing the toner to flow periodically, if an amount of change in the output voltage of the magnetic permeability detector 82 during a predetermined time is discriminated, a substantial error occurs. Hopper container 1 without straining
It is possible to detect whether or not there is a sufficient amount of toner 100 in 2.

In the above embodiment, the discrimination means 9
No. 8 analyzes and discriminates the fluctuation amount of the output voltage of the magnetic permeability detector 82. However, if desired, instead of this, during the predetermined time of the output voltage of the magnetic permeability detector 82, which may be, for example, 10 seconds. It is also possible to determine whether or not there is a sufficient amount of toner 100 based on the integral value in. Again, in this case,
As will be easily understood by referring to FIG. 6, there is no or extremely small possibility that an error will occur due to the change in the ambient temperature.

In order to satisfactorily avoid the occurrence of an error in the detection of the toner 100 by the toner detection means 80 described above, in the illustrated embodiment of the developing device constructed according to the present invention, the following technical construction is used. It should also be noted that has been adopted.

As already mentioned with reference to FIG. 2, the magnetic permeability detecting surface 86 of the magnetic permeability detector 82 has a horizontal angle of 0 ° <θ.
It is arranged so as to form an inclination angle of ≦ 90 degrees, especially 30 degrees ≦ θ ≦ 60 degrees, and the rotary flow member 92 rubs the magnetic permeability detection surface 86 of the magnetic permeability detector 82 from the lower side to the upper side. Is configured. With such a configuration, it is possible to sufficiently surely prevent the toner 100 from adhering to or staying on the magnetic permeability detecting surface 86 of the magnetic permeability detector 82 and adversely affecting the output voltage of the magnetic permeability detector 82. When the magnetic permeability detection surface 86 of the magnetic permeability detector 82 is inclined at an angle of 90 degrees or more with respect to the horizontal, or when the rotary flow member 92 is inclined from the upper side to the lower side, the magnetic permeability detection surface 86 of the magnetic permeability detector 82. When it is rubbed against the magnetic field, the magnetic permeability detector 8
The toner 100 tends to be excessively pressed against the magnetic permeability detection surface 86 of No. 2 and adhere or stay there.

Further, as will be easily understood by referring to FIG. 2, the rotary flow member 92 is replaced by the magnetic permeability detector 82.
When the magnetic permeability detection surface 86 is rubbed, the magnetic permeability detection surface 86 is elastically deformed into a convex shape protruding forward in the rotation direction. Then, when passing through the magnetic permeability detection surface 86 of the magnetic permeability detector 82, the rotary flow member 92 is elastically restored at least partially toward the straight extending shape. According to the experience of the present inventors, due to the above-described behavior of the rotating fluid member 92, the toner 100 that sticks to the front surface of the rotating fluid member 92 in the rotational direction is elastically restored to the rotational fluid member 92. At that time, there is almost no tendency for the toner 100 to be scattered from the front surface thereof, and thus the toner 100 to be adhered to the front surface of the rotating fluid member 92. However, if the cleaning means 90 is not provided on the rear surface of the rotating fluid member 92 in the rotating direction, some toner 100 adheres, and the adhered toner 100 adversely affects the output voltage of the magnetic detector 82. There is a risk. Thus, in the illustrated embodiment, FIG.
As will be clearly understood by referring to, when the rotary shaft 46 is rotated together with the rotary shaft 48, the tip end portion of the rotary cleaning member 94 disposed on the rotary shaft 46 comes to the rear surface in the rotational direction of the rotary fluid member 92. It acts to clean the toner 100 that may stick to it and thus to the rotating flow member 92.
Toner is sufficiently prevented from adhering to the rear surface in the direction of rotation. As a matter of course, the toner 1 is attached to the front surface of the rotating fluid member 92 in the rotating direction.
00 tends to adhere, the rotary cleaning member 94
In addition to or instead of this, a rotary cleaning member that acts on the front surface in the rotational direction of the rotary flow member 92 may be attached to the rotary shaft 36.

Continuing the description with reference to FIGS. 1 and 2,
It should also be noted the position in the hopper container 12 where the magnetic detector 82 is located. According to the experience of the present inventors, it is preferable to position the magnetic permeability detection surface 86 of the magnetic permeability detector 82 at a position where the toner 100 tends to stay in the toner transport paths 34 and 36. When the magnetic permeability detecting surface 86 of the magnetic permeability detector 82 is arranged at a position where the toner 100 in the toner conveying paths 34 and 36 is favorably conveyed, the toner 100 can be conveyed satisfactorily in the toner 100. In addition, a considerable air gap is accidentally generated, and the air gap may increase the apparent magnetic resistance of the toner 100, thus adversely affecting the output voltage of the magnetic permeability detector 82. On the other hand, toner 1
At the position where 00 is retained, the toner 100
The toner 100 is compressed by the retention of the toner and the generation of voids is sufficiently suppressed, and therefore, the adverse effect on the output voltage of the magnetic permeability detector 82 is sufficiently suppressed. In order to generate the retention of the toner 100 at the portion where the magnetic permeability detection surface 86 of the magnetic permeability detector 82 is located, at least one of the factors relating to the conveyance of the toner 100 is different between the upstream side and the downstream side thereof. This is very important. In the illustrated embodiment, at the upstream end of the toner transport path 36 where the magnetic permeability detection surface 86 of the magnetic permeability detector 82 is exposed, the toner 100 is laterally transferred from the downstream end of the toner transport path 34. Be transferred to
And a rotary shaft 48 at the upstream end of the toner transport path 36.
Due to the fact that the spiral blades formed on the upper end are the short spiral blades 70 and 72, the toner carrying capacity at the upstream end of the toner carrying path 36 is somewhat smaller than the toner carrying capacity at the upstream side thereof, thus Toner transport path 36
The toner 100 is configured to be retained at the upstream end of the. Of course, in a manner different from that of the illustrated embodiment, factors such as the toner conveying direction, the toner conveying ability, or the cross-sectional area (conveying area) of the toner conveying path are appropriately changed to generate the retention of the toner 100 at a predetermined portion. In fact, the magnetic permeability detection surface 86 of the magnetic permeability detector 82 can be exposed at such a portion. For example, it is configured that the toner 100 is supplied from the toner cartridge 14 to the hopper container 12 through the toner receiving port 42 to a certain extent, and the toner transport path 3 in the hopper container 12 is formed.
It is also possible to generate stagnation of the toner 100 at the upstream end portion of 4, ie, below the toner receiving port 42, and expose the magnetic permeability detection surface 86 of the magnetic permeability detector 82 to such a portion.

Further, in the illustrated embodiment, the magnetic permeability detector 82, the periodic flow means 88 and the cleaning means 90 are arranged at one end of the hopper container 12 below the other parts. It should also be noted that the recessed recess 96 is formed. As is well known to those skilled in the art, in a copying machine, usually, sufficient toner is not present in the toner supply means 4, and therefore, the development is repeatedly performed even after the toner is not supplied to the developing container 2, and as a result, As a result, when the toner concentration in the developing container 2 becomes lower than a predetermined value, a warning lamp (not shown), which may be a warning lamp, is activated to warn the user of the fact, and the copying is continuously performed. It makes it impossible to carry out the process. However, as an emergency evacuation measure,
Execution of the copying process each time is permitted. However, if the copying process is repeated once, the hopper container 1
If the concave portion 96 is not formed in 2, the following problems will occur. That is, because the toner concentration in the developing container 2 is below a predetermined position, the rotating shafts 46 and 4 in the hopper container 12 correspond to the execution of the copying process.
When 8 is rotated, the toner 100 existing in the hopper container 12 becomes extremely small. Thus, even if the rotary flow member 92 constituting the periodic flow means 88 is rotationally driven, the toner 100 is not allowed to flow on the magnetic permeability detection surface 86 of the magnetic permeability detector 82, and thus the magnetic permeability detector 82. The output voltage will not increase and will remain low. Therefore, the fluctuation amount of the output voltage during the predetermined time becomes a small value equal to or smaller than the predetermined value, and as a result, the determination means 98 of the toner detection means 80 determines that there is sufficient toner in the hopper container 12. there is a possibility. However, when the recess 96 is formed in the hopper container 12, the recess 96 forms a toner reservoir. That is, even if the amount of toner in the hopper container 12 becomes extremely small, the toner 100 in the recess 96 cannot be conveyed downstream, so that some toner 100 is always left in the recess 96. And the rotating shaft 4
When 8 is rotated and the rotary flow member 92 is rotated, the rotary flow member 92 acts on the toner 100 in the recess 96 to cause the toner to flow periodically on the magnetic permeability detection surface 86 of the magnetic permeability detector 82. Therefore, the output voltage of the magnetic permeability detector 82 is sufficiently varied, and the discriminating unit 98 discriminates that there is no error in the toner 100 in the hopper container 12 without error.

[0030]

In the developing device of the present invention, even if the toner is a weak magnetic toner, it is sufficient to determine whether or not a sufficient amount of magnetic toner exists in a predetermined area by using a magnetic permeability detector. Properly detected.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating a portion of a preferred embodiment of a developing device constructed in accordance with the present invention.

FIG. 2 is a sectional view showing a hopper container in the developing device of FIG.

FIG. 3 is a simplified block diagram showing a toner detection unit in the developing device of FIG.

FIG. 4 is a sectional view similar to FIG. 2, showing the hopper container in the developing device of FIG. 1 in a state where a sufficient amount of toner is present.

5 is a sectional view similar to FIG. 2, showing the hopper container in the developing device of FIG. 1 in a state where a sufficient amount of toner is not present.

6 is a diagram showing an example of actually measured data of an output voltage of a magnetic detector in the developing device of FIG.

7 is a sectional view similar to FIG. 2 showing the action of the cleaning means in the developing device of FIG.

[Explanation of symbols]

 2: Development container 4: Toner supply means 6: Developer application means 12: Hopper container 14: Toner cartridge 34: Toner transport path 36: Toner transport path 38: Toner discharge port 42: Toner receiving port 44: Toner transport means 46: Rotation axis 48: Rotation axis 80: Toner detection means 82: Permeability detector 86: Permeability detection surface 88: Periodic flow means 90: Cleaning means 92: Rotation flow member 94: Rotation cleaning member 96: Recessed portion 98: Discrimination means 100: toner 102: warning means

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[Procedure amendment]

[Submission date] February 5, 1996

[Procedure amendment 1]

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[Correction method] Change

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[Fig. 2]

[Procedure amendment 2]

[Document name to be amended] Drawing

[Correction target item name] Fig. 4

[Correction method] Change

[Correction contents]

FIG. 4

[Procedure 3]

[Document name to be amended] Drawing

[Correction target item name] Fig. 5

[Correction method] Change

[Correction contents]

[Figure 5]

Front Page Continuation (72) Inventor Koji Honda 1-22, Tamazo, Chuo-ku, Osaka City Mita Engineering Co., Ltd. In the company

Claims (19)

[Claims] 1. A developing device provided with a toner detecting means for detecting whether or not a sufficient amount of magnetic toner is present in a predetermined area, wherein the toner detecting means has a magnetic permeability exposed in the predetermined area. A magnetic permeability detector having a detection surface, a periodic flow means for causing the toner existing in the predetermined region to flow periodically toward the magnetic permeability detection surface of the magnetic permeability detector, and an output of the magnetic permeability detector. A developing device comprising: a determination unit configured to analyze a signal to determine whether or not a sufficient amount of toner exists in the predetermined area. 2. The toner is 0.1 to 5.0% by weight.
2. The developing device according to claim 1, wherein the developing device is a micro-magnetic toner containing the magnetic material. 3. The developing device according to claim 1, wherein the magnetic permeability detector has a form in which an output voltage changes in accordance with a magnetic resistance, and the determining means makes a determination based on a variation amount of the output voltage. 4. The magnetic permeability detector has a form in which an output voltage changes according to a magnetic resistance, and the determining means makes a determination based on an integrated value of the output voltage during a predetermined time. Developing device. 5. The periodic flow means is constituted by a rotary flow member which is driven to rotate and whose tip portion periodically rubs against the magnetic permeability detection surface of the magnetic permeability detector.
The developing device according to any one of 1 to 4. 6. The developing device according to claim 5, wherein a central axis of rotation of the rotary flow member extends substantially parallel to the magnetic permeability detection surface of the magnetic permeability detector. 7. The developing device according to claim 6, wherein the rotary flow member is formed of a synthetic resin film. 8. The magnetic permeability detecting surface of the magnetic permeability detector forms an inclination angle θ of 0 ° <θ ≦ 90 ° with respect to the horizontal, and the tip of the rotary flow member has the magnetic permeability detecting surface of the magnetic permeability detector. 8. The developing device according to claim 5, wherein the magnetic permeability detection surface is rotated in a direction in which the magnetic permeability detection surface is rubbed upward from below. 9. The developing device according to claim 8, wherein the inclination angle θ is 30 degrees ≦ θ ≦ 60 degrees. 10. The developing device according to claim 8, further comprising a cleaning unit that acts on a rear surface of the rotary fluid member in the rotational direction to remove the adhered toner. 11. The cleaning means comprises a rotary cleaning member that is driven to rotate, and a rotation center axis of the rotation cleaning member extends substantially parallel to a rotation center axis of the rotary fluid member. 11. The developing device according to claim 10, wherein the rotating direction of the rotating fluidizing member is opposite to the rotating direction of the rotating fluidizing member, and the tip of the rotating cleaning member acts on the rear surface of the rotating fluidizing member in the rotating direction. 12. The developing device according to claim 11, wherein the rotary cleaning member is formed of a synthetic resin film. 13. The predetermined region is in a magnetic toner transport path, and at least one factor relating to toner transport changes in the upstream side and the downstream side of the predetermined region due to toner retention in the predetermined region. The developing device according to any one of claims 1 to 12, wherein: 14. The carrying capacity of an upstream toner carrying means arranged upstream of the predetermined area is larger than the carrying capacity of a downstream toner carrying means arranged downstream of the predetermined area. 14. The developing device according to claim 13, wherein the toner retention is generated due to. 15. The developing device according to claim 13, wherein the toner retention is generated due to the toner transport direction being abruptly changed in the predetermined region. 16. The predetermined area is formed with a concave portion for forming a toner reservoir, and the periodic flow means also acts on the toner present in the concave portion. The developing device described. 17. A developing container, a developer applying means for applying a developer existing in the developing container to an electrostatic latent image to be developed, and a toner supply for supplying a magnetic toner to the developing container. Means for supplying magnetic toner through the hopper container in which a toner transport path having a toner receiving port and a toner discharge port communicating with the developing container is formed, and the toner transporting route. The developing device according to any one of claims 1 to 16, further comprising a transporting unit for transporting, and the predetermined region is in the toner transporting path formed in the hopper container. 18. The developer present in the developing container is a two-component developer composed of carrier particles and magnetic toner.
The developing device according to claim 17. 19. The toner supply means includes a toner cartridge which is replaceably mounted, and the magnetic toner accommodated in the toner cartridge is fed to the hopper container through the toner receiving port. 19. The developing device according to item 19.